Skills of argument are important for effective consideration of social issues and participation in democratic institutions. Such skills applied to a juror-reasoning task have been found to have a relationship with how well possible verdict choices might be considered. As justice in the jury system requires that jurors give full consideration to the evidence and can find the best fit between evidence and a verdict, the fostering of cognitive skill applied to everyday, non-schooled reasoning contexts is essential. This synthesis of findings from a juror-reasoning project, drawn from a sample of 180 people on jury duty, shows that skills of argument applied to the juror task can be identified and are consistent across contexts and with other skills. It also shows that education and the development of epistemological understandings play roles in variation found in informal reasoning and open-minded consideration of others' claims. The following are appended: (1) Epistemic Reasoning Task--Accounts of the "Fifth Livian War"; (2) Epistemic Reasoning Task--Interview Questions; (3) Synopsis; and (4) Juror Interview. (Contains 7 tables.)